STEADY-STATE MODEL OF A ZIRCONIA OXYGEN SENSOR IN A SIMPLE GAS-MIXTURE

The theory of gas sensors developed previously is used to analyze in d etail the response of a zirconia oxygen sensor exposed to a mixture co ntaining oxygen and a single reducing gas such as CO or hydrogen. Resu lts for changes in the sensor e.m.f. as a function of the inverse redo x ratio (defined as twice the ratio of the partial pressure of oxygen to that of the reducing gas in the cases cited) due to variations in g as diffusion, adsorption, desorption, and Pt electrode surface-reactio n rates are presented. The response of the sensor to a fully equilibra ted gas mixture is also described.